It is similarly annoying to them when it is a long free text box, making the customer question whether they are answering correctly and sufficiently. Providing response boxes that reflect the anticipated answer length and format reassures people that they are filling them in correctly.

People from different cultures have different conventions for answering seemingly innocuous questions like this. Users will become frustrated if when you ask for an email address, for example, if the response box only allows for 20 characters.